Despite a constrained and vulnerable system, no load-shedding is expected on Saturday, Eskom said.

But the power utility warned that the current high level of unplanned breakdowns was of concern.

“As the generating plant continues to perform at low levels of reliability, we are experiencing a high level of breakdowns, which are sitting at 15,921MW as at 6.30am this morning.

“The current high level of unplanned breakdowns is of concern and our teams are working flat out to ensure that the risk of load-shedding is minimised as SA returns to work from January 6. We will be working on returning some generating units to service during this weekend including Koeberg Unit 1, which will start feeding into the grid,” Eskom said in a statement.

It added that it would continue to use emergency reserves to supplement capacity if necessary.

“We however remind customers that as the system continues to be vulnerable and unpredictable, the possibility of load-shedding remains.

“Eskom requests all South Africans to continue to use electricity wisely, particularly during peak hours in the morning and early evening.”

Meanwhile, several parts of Johannesburg, including the CBD, were without power on Saturday morning due to a trip at the City power Central Incomer substation.

“The trip happened on Eskom side at around 3am this morning. It is not yet clear what caused the trip,” City power said.